Administration of injections causes trauma to underlying tissues. In many cases, such as when vaccines are administered in a doctor's office or a peripheral venous catheter is placed during a short a hospital stay, the tissue is only exposed to medication for a short period of time and the tissue has an opportunity to heal before it is subjected to more trauma. As a result, few complications occur when injections occur sporadically. However, for those patients that have chronic conditions or diseases, such as diabetes, repeatedly injecting the same area of the body or placing infusion sets or similarly invasive devices in the same area of the body can result in complications that affect a patient's ability manage his or her disease. Rotation of injection/insertion sites is required for effective management of chronic conditions.
In some cases, repeated injections result in the formation of masses of fibrocollagenous scar tissue at the injection site. Localized lipodistrophy, or loss of fat, may also occur as a result of trauma and also as a result of exposure to medications or treatments being administered subcutaneously. The repeated subcutaneous administration of insulin in the same area can also lead to lipohypertrophy, the accumulation of hardened pocket of fat under the skin. Lipohypertrophy occurs at the injection sites of diabetic patients because insulin has a hypertrophic effect on fat cells—it causes fat cells to get larger.
When the underlying tissue around an injection site changes, the body's ability to absorb whatever is being injected into that site also changes. As a result, the efficacy of medications delivered into the subcutaneous tissue changes. In the case of patients having diabetes, changes in absorption can contribute to variable glucose levels (hypoglycemia or hyperglycemia), leakage and therefore loss of the injected insulin dose from under the skin, and reduced or slowed absorption of insulin resulting in gradual increases in insulin dosage (as much as a 20% increase over the course of a year). Changes in underlying tissue can also reduce the availability of healthy injection sites to a patient.
An international survey on insulin injection technique (DeConinck C et al., “Results and analysis of the 2008-2009 insulin injection technique questionnaire survey”, Journal of Diabetes 2010; 2:168-179) revealed that: 47% of the participants had experienced lipohypertrophy and this was associated with repeated injections into a site smaller than a postage stamp. The survey also revealed that 28% of the participants could not remember ever having their injection sites checked by a health care provider. The survey also indicated that higher A1C levels have been reported with patients injecting into lipohypertrophic sites, indicating that lipohypertrophy contributes to changes in insulin absorption. Clearly there exists a need to rotate injection sites and to monitor injection sites for complications in order to effectively manage chronic conditions, such as diabetes, that require repeated injections.
Another factor that contributes to the high rate of lipohypertrophy or similar tissue damage is the reuse of needles/injection devices that are intended to be sterile, disposable, single use items. A recent study by Berard L. et al., “Injection technique practices in population of Canadians with Diabetes: Results from a recent patient/diabetes educator survey”, Canadian Journal of Diabetes, (2015), Vol. 39, Issue 2, 146-151, indicated that only 60.7% patients dispose of a needle after use (use the needle only one time. The table below shows the number of times a patient uses a single-use needle versus the percentage of patients. Nearly 40% of the population surveyed re-uses single use, disposable needles, with 30.2% of the population reusing these needles 2 to 5 times.
Number of time(s)Over1234567891010%60.7%13.0%8.4%5.2%3.6%2.3%0.8%0.4%0.2%1.0%4.4%patients
Reuse of needles or injection devices increases trauma at the injection site because a needle is damaged, bent, and/or dulled each time it penetrates the skin. Thus, while reusing a needle might seem economical and convenient, it results in increased trauma at the injection site and increasingly painful injections. Further, reuse of needles increases the opportunity for infection. Devices intended for self-injection/auto-injection vary from syringes having an integrated needle permanently or semi-permanently incorporated to insulin pens whereby a sterile, disposable pen needle is attached to facilitate drug container access allow fluid egress from the container through the needle into the patient to single use pen-style injectors. However, none of these devices intend for the portion of the device that penetrates a patient's skin to be reused. Exemplary devices used to inject self-administered medication via a combination of a pen injector and a sterile, single use pen needle are disclosed in U.S. Pat. No. 7,645,264 B2 (Marsh) or U.S. Pat. No. 8,882,706 B2 (Cronemberg), and in Canadian Patent Application No. 2 858 665 (Herr). Given the high rate of reuse of needles, there also exists a need to remind or prompt a patient or user to use a new needle for each injection to reduce complications that occur as a result of repeated injections at a limited number of injection sites.
In the survey by Berard L. et al. mentioned above, the vast majority of participants (80.4%) injected medication into the abdomen; 36.6% had no explicit injection routine, and 31.4% injected into the same site at the same time each day. Overall, 24.6% of patients observed lipohypertrophy at injection sites, while only 13.3% of diabetes educators observed the same complication. In order to maximize efficacy of an insulin or other injection regimen and minimize complications resulting from repeated injections at the same site, there exists a need to facilitate creation of and compliance with a personalized injection plan for diabetic patients and others patients that receive frequent subcutaneous injections.
U.S. Pat. No. 7,857,138 B2 (Temple) teaches a system for organizing and storing pre-determined dosages of medication by matching indicia on both the storage apparatus and the apparatus containing the medication. The invention by Temple is particularly directed to a method for administering the good dosage but does not resolve the problem of changing needles and injection sites.
US Patent Application Publication Nos. 2013/0144256 A1 (Wessel et al.) and 2014/0188074 A1 (Jacques R. et al.) teach usage of a medical marking apparatus and tattoo activation device containing a medical ink barrel. This method will increase the complications of injection and administration of medication because it adds extra mechanical parts to the injection device and extra steps to each injection. This method might not be well accepted by the patient, because it creates random ink marks on the skin, which can be unpleasant for the patient. A similar injection site marking method is disclosed in U.S. Pat. No. 8,574,194 B2 (Taylor), but has the same drawbacks mentioned above.
International Patent Application No. PCT/US2014/068469 (Fiedler et al.) discloses providing injection devices having removable markers that are pre-associated with different injection sites to facilitate an injection regiment, with the markers being removed from the injection devices and applied to a physical or electronic chart to track compliance with an injection regimen. The removable markers, however, can easily be lost or damage when carrying injection devices, and carrying a chart and applying a sticker to it each time an injection is administered can be burdensome to a patient/user/caregiver. Further, pre-assignment of injection sites can present problems because it does not account for the needs of users or patients. Not all injection sites are suitable for all users, for example, because of the condition of underlying tissue, accessibility, and/or pain. In one embodiment, Fiedler et al. discloses that injection devices can be provided in a compartmentalized container, where each compartment corresponds to part of an injection scheme. In practice, however, users do not carry large containers of injection devices around on a daily basis. A user carries only those injection devices he or she will need for the day (or trip), along with emergency supplies in case of delay. Thus, any association based on compartmentalization will be lost in daily use.
Thus, there exists a need for new tools and methods that can be personalized to the needs of an individual, yet are easy to understand and implement, in order to help patients to integrate regular change of the needle and rotation of injection site to their daily disease management routine.